Process of galvanizing metals.



No. 645,520. I I S Paten ted Mar. l3, I900. E. I. BRADDOCK.

I PROCESS OF GALVANIZING METALS.

(Application filed Dec. 23, 1899.)

(No Model.)

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UNIT D STATES,

PATENT I "Fares,

EDWARD I. BRADDOCK, OF WINCHESTER, MASSACHUSETTS, ASSIGNOR TO THE NEW PROCESS COATING COMPANY, OF PORTLAND, MAINE.

PROCESS OF GALVANIZING META-LS.

SIPECIFICATION formirng; part of Letters Patent No. 645,520, dated March 13, 1900.

Application filed December 23, 1899.

To all whom it may concern.-

Be it known that I, EDWARD I. BRADDOOK, a citizen of the United States, residing in Winchester, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Processes of Galvanizing Metals, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts. I

This invention relates to a novel method of galvanizing iron or steel strips, sheets, plates, wires, &c., and has for its object to cheapen the cost of galvanizing and at the same time improve the product by obtaining on the iron or steel a coating which is smooth, light, 'pliable, and does not crack when the iron or steel strip, plate, &c., is bent. For this purpose I employ a galvanizing-bath composed of zinc or its alloys, and preferably of zinc and tin, and a body of lead or its alloys, and preferably lead and tin, upon a portion of Y which the galvanizing-bath rests and from which the dross formed is automatically removed. The baths are contained in a tank or vessel, which is of suitable construction, so as to leave a. portion of the lead-bath exposed and uncovered by the galvanizing-bath, so that the iron or steel strips after being properly cleansed and fluxed may be first passed into the lead-bath and then out therefrom through the superimposed bath of zinc and tin. The lead-bath after little use becomes alloyed with a portion of the tin of the galvanizing-bath, and consequentlyl prefer to start with a bath of lead and tin, in which case the tin does not appear to be taken or extracted from the galvanizing-bath. The apparatus is further constructed so that the dross formed by contact of the iron or steel may be automatically removed substantially as fast as formed.

Figure 1 is a longitudinal section of one form of apparatus with which'this invention may be practiced, and Fig. 2 a transverse section of the apparatus shown in Fig. 1 The apparatus herein shown comprises an outer vessel or kettle a, a smaller inner vessel b, and a partition-wall 0, extended between said vessels, so as to form a substantially-narrow chamber d on one side and a substantially wide chamber e on the other side of said par- Serial No. 7411394. (No specimens.)

tition-wall,whichlatterchamber'extends over of galvanizing metal or metals, preferably zinc and tin, (indicated by the broken lines It.)

In'practicing the process with the apparatus herein shown the iron or steel strip, sheet, plate, &c., after being suitably cleansed and fluxed is passed through the bath h of lead. or lead and tin contained in the chamber 62 and passage f and up through the galvanizingbath 7c of zinc and tin, which bath I have ascertained effectively galvanizes the iron or steel with a firm yet light or thin coating, which is very pliable and does not crack when the galvanized piece. is bent, thus enabling the galvanized piece to be freely bent and hammered without injuring thegalvanizingcoating, consequently enhancing the value of this product. The tin in the zinc-bath imparts to the galvanizing-bath more fluidity, rendering it more ductile and easier to run, sothat a very thin coating on the iron or steel efiectively galvanizes the same with a minimum consumption of galvanizing metals.

By passing-the iron or steel strip, 850., first into the bath of lead or lead and tin waste of galvanizing metal by spattering or flying is avoided. So, also, it will be noticed that the iron or steel strip,&c.,passes but once through the galvanizing metal, and in practice the galvanizing-bath resting on the bath of lead or lead and tin may be made shallow, thus reducing to a minimum the contact of the iron or steel with the galvanizing metals, which reduces to a minimum the amount of dross formed. As the dross is formed on the surface of the lead-bath beneath the galvanizing-bath it overflows into the inner vessel and, being heavier than the zinc, descends to the bottom of the said vessel.- In this manner the dross is automatically removed and is'prevented from accumulating on the surface of the lead-bath to any great extent, thereby reducing to a minimum the amount too of dross through which the iron strip, 850., is

passed, and consequently reducing to amini= mum the liability of dross adhering to the l strips, plates,wire's, itc.,whicli consistsinfirst galvanized strip, thus imparting to said galvanized strips a smooth surface free from lumps and avoiding liability ofthe coating on the iron strip being cracked when the said 7 strip is bent.

As stated above, I prefer to start with a bath of lead and tin, but I may start with a bath of lead alone; but after a short time a portion of the tin in the galvanizing-bath mixes with the lead-bath, which thereafter makes the said bath one of lead and tin. The tin in the lead-bath acts beneficially on the iron or steel strip, and the latter on its passage through said bath is partially or wholly coated with tin and is thus efiectively prepared for the reception of the galvanizingcoating of zinc and tin. I prefer to employ the baths hereinbe'fore mentioned; but the process herein described may be advantageously practiced with the galvanizing-bath composed of zinc alone.

The bath composed oflead and tin may and preferably will be made up of threeparts lead to one part tin, and the galvanizingbath may and preferably willbe madeup of sixteen part-s zinc to one part tin. The vessel b may be. suspended in the vessel (1 by straps or hangers p.

I claim 1. The method of galvanizing iron orsteel passing the said strip, 850., into a bath of lead or its alloys, passing said strip out therefrom through a layer or substantially-shallow bath of zinc or its alloys, resting on a portion only of said lead-bath, and reducing toa minimum the amount of dross through which the iron or steel strip, &c., is passed by continuously removing the dross fromthe surface of contact of the zinc and lead substantially as fast as formed, substantially as described.

2-. The method of galvanizing iron or steel strips, plates, wires, &c., which consists in passing the said strip, &c., into a bath of lead and tin; passing said strip out therefrom through a layer orsubstantially-shallow bath of zinc and tin resting on a portion only of the bath of lead and tin; andreducing to a minimum the amount of dross through which the iron or steel strip, &c., is passed by continuously removing the dross from the surface of contact of the zinc and lead substantially as fast as formed, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

EDWARD I. BRADDOCK.

WVitnesses:

J AS. H. CHURCHILL, J. MURPHY. 

